Referee Tony Weeks controversially stopped the fight when many believed the Russian could have continued despite an eighth round onslaught from the American.

A telling right hand followed by numerous body shots, which Kovalev felt were low, ultimately proved decisive in a thrilling, high octane fight.

Here's how the action unfolded...

Will Griffee

Host commentator

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05:21

Thank you for your company tonight!

Well that certainly lived up to the billing. An incredible eight rounds of action and Andre Ward was unquestionably in the ascendancy following his eighth round onslaught but referee Tony Weeks' stoppage will leave a bitter taste in the mouth.

Will Ward grant Kovalev another crack at it? Who knows, but many sat ringside had the Krusher up on the scorecards with four to go.

Ultimately, the aggression and heavy jab of Kovalev were negated by Ward who gradually grew into it and his record remains perfect. I hope you enjoyed that as much as I did, and be sure to join Sportsmail next time. Goodnight!

Andre Ward knocked out Sergey Kovalev with some punishing body shots and celebrated in style

Kovalev was rocked in the eighth round which proved to be the beginning of his demise

04:58

Kovalev: 'Low blow followed by low blow'

'I don't know why stopped the fight,' Kovalev agrees that the stoppage was far too early. 'This is fighting, we are boxers, he punched me but he didn't hurt me, I want a rematch at once, I didn't agree with the decision.'

04:56

Ward: ''When you hurt the body, go back there'

Ward thanks God, his wife and his nasty body shots. The 33-year-old talks the crowd through his finish, saying his body shots were borderline but he felt it was inevitably going to be stopped after the thunderous right hand.

Andre Ward celebrates with his belts following the stoppage win against Sergey Kovalev

04:51

STILL THE UNDEFEATED LIGHT HEAVYWEIGHT CHAMPION OF THE WORLD

Andre 'SOG' Ward said he would deliver something special and he has. Such a shame that this one ended in controversial circumstances. It looked like Ward was going to find a way to win in that round but Weeks stopped it far too early.

Many had Kovalev narrowly ahead on the scorecards but Ward came into it as the fight progressed and a massive right hand was the beginning of the end.

Andre Ward celebrates on his knees and thanked God and his wife following the win

04:49

Controversy in Mandalay Bay!

Kovalev is fuming. He feels there were clear low blows in that round but Ward doesn't care. Few called this one by stoppage for the American but he picked Kovalev apart in that eighth round. It seems like a premature stoppage from Weeks after two consecutive body shots, a crazy decision with Kovalev still able to defend himself, but Ward has done it again. Incredible.

Nice body shots from Kovalev but the former Olympic champion Ward. Kovalev is hurt! A body shot is deemed legitimate and Ward has landed a telling blow. Huge right hand from Ward! Body shots on the ropes! It is all over

'SOG' rings out around Mandalay Bay. This fight is still hanging in the balance but the express jab of Kovalev persists.

The Russian tries to claim a low blow but Tony Weeks is having none of it and waves him to continue, does that indicate a shift in the mental approach of Kovalev?

Both men looked to land body shots on the inside but neither found a clear advantage

04:39

As with the last fight, Ward is growing into it but needs to stay totally switched on because Kovalev can end this at any time.

Kovalev works well when he forces Ward onto the ropes but the American ends the round with a flurry, always nice to leave a positive image in the minds of the judges. The Krusher landed a brilliant right hand in that one and both men are using the jab to great effect.

Sergey Kovalev (left) dominated the close exchanges but Ward started to utilise the jab well

04:35

Kovalev isn't being drawn into throwing anything silly but Ward lands a thudding left hook. The Russian takes it well but is bleeding from his nose. This is a great fight, so much skill on show but it is tactical as well as thrilling.

Ward is growing into it and being more creative as the fight goes on but both men look drained in their respective corners. Another one too close to call but Ward's left hook was the shot of the round.

04:31

Better from Ward. Some clean work from the man from Oakland as he out-boxes the Krusher.

After dominating the early exchanges, Kovalev knows he's in a real contest now. Much more of a high octane battle than the first encounter and if this pace persists it will be a miracle if the judges are required again.

04:27

They say familiarity breeds contempt and that seems to be the case with these two. No love loves in the build up and they know each other inside out.

Kovalev just seems to have that power advantage and cuts off the ring, forcing Ward to work hard from areas he doesn't want to be.

The pair open up in the final ten seconds of the round, another razor thin one to call but Kovalev seemed to shade it and landed a lovely right hand over the top.

Sergey Kovalev used his jab to good effect early on and looked to cut off the ring

04:22

Kovalev is busy but Ward's head movement is excellent. So many faints from the 33-year-old to keep his challenger guessing.

You can see why this one was so close last time out but Kovalev lands the punch of the round with a stinging right hand. The referee calls a halt to proceedings with a low blow from Ward. Great round and I'd give that one to Kovalev.

04:15

HERE WE GO!

In the first fight between these two Kovalev floored Ward in the opening round. The American has started in a relaxed, back-foot stance with his opponent the aggressor.

Ward lands a couple of stinging blows but Krusher finds his piston-like jab. Tough to call that opener.

04:10

'Son of God' Ward strolls into the limelight

Andre Ward who calls himself 'Son of God' but has been nicknamed 'Son of Judges' by Kovalev after last time, edges his way to the squared circle and we're not far away from getting this one going.

04:07

Here comes the 'Krusher'...

Sergey Kovalev is deep in the bowels of Mandalay Bay, making his way to the ring as Hall of Fame MC Michael Buffer dusts off the vocal chords to announce the challenger.

04:03

Pound-for-pound #1 vs #2

With the protagonists only minutes away from their ring walks the crowd are bubbling nicely in Las Vegas. Ringmagazine rank Ward #1 and Kovalev #2 in their pound-for-pound rankings so expect another close fight with the Russian attempting to bully his American foe.

03:57

The 'Bomber' has his say...

Off to bed! Ward on points for me! It's a brilliant fight that has had me questioning myself all week! Kovalev KO was tempting BUT Ward UD👊